This invention refers to a process to manufacture "in situ" safety barriers for roads and highways, being applicable also to the manufacturing of special curbs.
In the making of roads and as a means of separation and safety between opposite traffic ways, it is necessary to install a protecting member intended to fulfill two main objectives:
a) To prevent a vehicle that has suffered an accident from invading traffic lanes for cars travelling the opposite way; and PA1 b) To allow the passage of water in case of rain or flood, there being a passage under said protecting member so that there is no stagnation of water flooding a given way, flooding which may otherwise result in interrupting traffic or at least causing an accident. PA1 (1) Slow manufacturing. PA1 (2) Big stacking areas. PA1 (3) High costs, because the expenses for the concrete are incurred since the early step of manufacturing, resulting in high storage costs or delays in supplies because of slow manufacturing. PA1 (4) Great difficulty in handling, with cranes and personnel being required, resulting in a slow handling. PA1 Manufacturing speed. PA1 Visibility of a barrier as it can be manufactured in any color. PA1 Handling ease. PA1 Marking speed. PA1 Replacement ease. PA1 Reduction of installation costs without any type of soldering processes, special attachments, etc. on site. PA1 Minimal and economical maintenance. PA1 Possibility to incorporate soft strip to limit the mould. PA1 Possibility to use the mould or moulds as a marking means, combining units with different colors, for instance, red and white. PA1 Economy and terms. PA1 Higher finishing quality. PA1 Possibility to use any semi-rigid fixing system between moulds. PA1 Possibility to make the moulds in any geometric shape, adapting to the requirements of each application. PA1 Use for fixed protection. PA1 Use for mobile protection. PA1 Use as ecological barriers. PA1 Use as an acoustic signal in mobile works. PA1 Protection to the driver, barriers filled with concrete. PA1 Protection to the highway worker, barriers filled with sand, water or expanded polyurethane. PA1 Protection to pedestrians and environment, ecological barriers.
One way of manufacturing said safety barriers is shown in FIG. PA-1 which consists of some sheet strips (1) coupling rigidly to small metal pillars (2) nailed to the ground. This safety barrier performs the required functions of limiting and absorbing the kinetic energy of the mass of the vehicle and allowing the passage of water. This type of structure has drawbacks in that it is not particularly durable and can be permanently deformed by relatively low impacts. This results in high maintenance costs.
Another way of manufacturing such safety barriers is shown in FIG. PA-2, which is based on concrete blocks (3) in mass prefabrication, in a shape more or less arched and joined together semi-rigidly and with a great enough mass to withstand the shock and impact of a vehicle. These blocks have on their underside projections or legs (4) to allow the passage of water.
The blocks have usual minimum dimensions of 70 cm wide, 80 cm high and 100 cm long. Taking into account the concrete density, the mass of each member or block will be approximately 1,175 Kg. With regard to the previous system, it has the advantage that its maintenance is practically nil.
In both cases, the safety barrier is installed when the road is quite finished, including in said finishing the rolling layer, road borders, etc.
As the process referred in the present invention is intended to replace the barriers made from prefabricated concrete members, the features of this manufacturing method are going to be analyzed, that is, the features of the barriers made of prefabricated concrete blocks, which have the following characteristics.
Material: The concrete must be white and made by using white cement or cement from some quarries of special materials that give a light-colored texture. The typical strength is between 150 and 175 Kg/cm.sup.2.
Manufacturing: it is performed in factories duly provided with enough moulds. The process is as follows: filling of the concrete moulds, vibrating, setting and subsequent unmoulding. Because of the weight of each block, loading and unloading for storage is done with a crane.
Storage: The area of each block is 700 cm.sup.2 (100.times.70 cm), being the height with legs approximately 77 to 85 cm.
From the foregoing, it is easy to note the great difficulty to store the blocks, because they cannot be stacked and must remain nearby. Let us consider the required area for storage. Let us take a road of 10 Km that requires the manufacturing of 10,000 blocks. The minimum storage area must be 1,000 m.sup.2, that is, an area bigger than a football field.
Handling: It always requires a crane and the assistance of one or more workers.
Transport: By using a truck of 2.50 m.times.10 m, the amount of 1 m long blocks that the truck can carry will be 35 units maximum, this limitation caused by their area and mass.
Handling at work: The minimum number of operations at work is two, stacking on the edge of a road and mounting in the final location in the middle of the road.
Terms: At present, public works depend on the economic factor and also on the termination term, so that the time required to finish a road through concrete barriers must be necessarily long, because there are four main disadvantages: